OOP Spaghetti code explained

The term "spaghetti code" is usually attributed to pre-OOP code, but there is a lot of OOP code out there that is definitely entangled and a mess. I have seen quite some of it in my carreer, and this kind of spaghetti is characterized by its dependencies. An class is nothing else than a data structure with associated code, mainly written in a way that puts both into the same source code file.